October 13, 2006 Global Design Effort 1 International Linear Collider Machine Detector Interface Materials for discussion at Engineering Forum: experiences from LHC detectors conception and construction CERN, October 13 Andrei Seryi, Hitoshi Yamamoto

Oct 13, 06 Global Design Effort ILC-MDI: 2 Thanks To many colleagues from CERN and other labs who were involved in discussion and work on the issues described in this talk To everyone who organized this meeting, who were guiding the tour, and who are participating in this meeting

Oct 13, 06 Global Design Effort ILC-MDI: 3 Contents Introduction, ILC and BDS layouts Detector assembly, hall sizes, arrangements, etc –Adopted on-surface assembly concept for ILC –Consider pure CMS or modified CMS assembly Questions associated with study of push-pull –Detector design and radiation shielding –Moving detector parts –Location of services and electronics, etc Goal of this meeting: learn CERN experience and consider how to best apply it to ILC

Oct 13, 06 Global Design Effort ILC-MDI: 4 ILC layout This shows central location of DR which is not yet officially accepted

Oct 13, 06 Global Design Effort ILC-MDI: 5 Beam Delivery System layout IP2 IP1 10m 1km beam dump service hall alcoves 9m shaft for BDS access polarimeter laser borehole muon wall tunnel widening

Oct 13, 06 Global Design Effort ILC-MDI: 6 beam dump service hall alcoves 9m shaft for BDS access & service hall beam dump and its shield muon wall tunnel widening Beam Delivery System tunnels

Oct 13, 06 Global Design Effort ILC-MDI: 7 Couple of particular features It is worth to attract attention and discuss couple of particular assumptions: –Do not include (unlike LHC) a separate service cavern for detector equipment and electronics. All what is needed is placed in the collider hall. –Do not have access shafts than those 2 in IR hall, and these shafts are equipped with elevators and stairs: (The nearest shafts for machine assess are ~600m from IP) Picture shows a solenoid being lowered down in an IR hall shaft

Oct 13, 06 Global Design Effort ILC-MDI: 8 On-surface (a la CMS) assembly Schedules of ILC CFS work developed by Martin Gastal and his colleagues –According to tentative CF&S schedule, the detector hall is ready for detector assembly after 4y11m after project start –If so, cannot fit into the goal of “7years until first beam” and “8years until physics run” Surface assembly allows to save years and allows to fit into this goal –The collider hall size may be smaller in this case –A building on surface is needed, but savings may be still substantial Adopted on-surface assembly for ILC

Oct 13, 06 Global Design Effort ILC-MDI: 9

Oct 13, 06 Global Design Effort ILC-MDI: 10 On-surface detector assembly Underground detector assembly VERY TENTATIVE start date is arbitrary

Oct 13, 06 Global Design Effort ILC-MDI: 11 Versions of on-surface assembly Accepted on-surface assembly Still, discuss variations –pure CMS assembly (config B) –modified CMS assembly (config A) Assemble smaller (than CMS) pieces on surface, lower down and perform final assembly underground May affect schedule (?), but preliminary looks by a small bit less expensive than “B” Details of assumptions shown on next pages –would like to clarify our understanding and perhaps refine the ILC assumptions during this visit to CERN

Oct 13, 06 Global Design Effort ILC-MDI: 12 Table if IR assumptions continued at next page=>

Oct 13, 06 Global Design Effort ILC-MDI: 13

Oct 13, 06 Global Design Effort ILC-MDI: 14 Single IR questions GDE is studying a design with single IR and two detector (“push-pull” case) Questions associated with study of push-pull –Detector design and assembly –Radiation shielding –Moving detector parts and shielding –Location of services and electronics, etc Detailed list of questions here: Some tentative conclusions are below

Oct 13, 06 Global Design Effort ILC-MDI: 15 Example of questions What is the suitable way to move (rails, air-pads) the detector? –air-pads seems as a possibility For quick change-over, do we need to make detector self shielding? –It would help, but self-shielding is not absolutely required for quick change-over What are the design changes needed to make the detector self shielded? –For GLD, self-shielding has been shown in simulations. For the fourth detector concept (double solenoid with no iron), implementing self- shielding may be difficult If there is a need in shielding wall between detectors, what is the method of its removal and assembly? –The shielding wall, if needed, can consist of two parts and move on air- pads in hours What arrangements or reinforcements (such as imbedded steel) are needed for the floor of the collider hall? –Steel plates (~5cm thick, welded) to cover the collider hall floor How the connections of electrical, cryo, water, gas, etc, systems are arranged? –Part of electronics and services can be placed on a platform which moves with detector. Flexible connections to stationary systems needed.

Oct 13, 06 Global Design Effort ILC-MDI: 16 accessible during run (radiation worker) accessible during run (general personnel) not accessible during run fence Platform for electronic and services (~10*8*8m). Shielded (~0.5m of concrete) from five sides. Moves with detector. Also provide vibration isolation. Concept which does not rely on self-shielding detector

Oct 13, 06 Global Design Effort ILC-MDI: 17 Detector assembly and its radiation safety properties Although not required, eliminating the shielding wall would facilitate the push-pull case –In this case, If the off-beamline detector is to be accessible, the detectors should be self-shielded Preliminary study indicate that most of ILC detectors can be made self-shielded even for pessimistic assumption of full beam loss (18MW) Question is: are there any particular constraints, due to on-surface assembly, which complicates design of self-shielded detector?

Oct 13, 06 Global Design Effort ILC-MDI: 18 Results show that GLD can be self-shielded even if assume criteria of 25rem/h (250mSv/h) for maximum credible incident [SLAC rule] at any place (=loss of 18MW beam at thick target) Shield around beamline was not included Self-shielding study of GLD

Oct 13, 06 Global Design Effort ILC-MDI: 19 Yasuhiro Sugimoto GLD modified to improve self-shielding

Oct 13, 06 Global Design Effort ILC-MDI: 20 The 4 th detector concept Magnetic field lines of the 4th Concept, showing the dual solenoids and the “wall of coils” on the ends. A cut-away view of the dual solenoids and the “wall of coils” that terminate the solenoid field in the 4 th Concept. Featuring the dual solenoids and no need for the iron return yoke The calorimeter, solenoids and supporting structures give some shielding but certainly not sufficient self-shielding If it were to be made self-shielding, ~2-3m of concrete would need to be added around the detector. Or has to rely on external shielding wall

Oct 13, 06 Global Design Effort ILC-MDI: 21 IR hall with shielding wall No shield around beam With shield around beam May need additional curtain wall on top of main wall. May need shaft cover. Do not need full height wall. The height could be decrease from what shown.

Oct 13, 06 Global Design Effort ILC-MDI: 22 A.S: Is it possible to avoid the gaps between slices, in particular for cables, or at least avoid direct view to the beam through the gaps? A.Herve: Minimum gaps are needed for cables and gas/cooling pipes. But gap do not point on IP Surface assembly & self shielding

Oct 13, 06 Global Design Effort ILC-MDI: 23 A.S. Q: Is it possible to arrange layers of irons in such a way that the direct view to the beam through the gaps would be avoided? As is, with gapsModified A.Herve: For CMS, to see the beam pipe is not a problem for the gap is behind the calorimeter. Field map would be affected and more complicated. Closure of the detector would be more complex. 3D interface instead of 2d IP A.S. Q: For total self shielding we probably has to assume that the beam loss can happen not only at IP, but at any place?

Oct 13, 06 Global Design Effort ILC-MDI: 24 Summary Looking forward to discuss the issues of detector assembly, radiation safety design, IR hall arrangements, etc.

Oct 13, 06 Global Design Effort ILC-MDI: 25 Backup slides

Oct 13, 06 Global Design Effort ILC-MDI: 26 Self-shielding study color scale is different in two cases 18MW on Cu target 9r.l at s=-8m Pacman 0.5m iron and 2m concrete 18MW on Cu target 9r.l at s=-8m Pacman 1.2m iron and 2.5m concrete 18MW at s=-8m: Packman dose at pacman external wall dose at r=7m Fe: 0.5m, Concrete:2m 120rem/hr (r=3.5m) 23rem/hr Fe: 1.2m, Concrete: 2.5m 0.65rem/hr (r=4.7m) 0.23rem/hr A proper beamline shielding can reduce the dose below 25rem/hr Desired thickness is in between of these two cases Alberto Fasso et al

Oct 13, 06 Global Design Effort ILC-MDI: 27 If detector does not provide any radiation protection: For 36MW maximum credible incident, the concrete wall at 10m from beamline should be ~3.1m Wall 18MW loss on Cu target 9r.l \at s=-8m. No Pacman, no detector. Concrete wall at 10m. Dose rate in mrem/hr. 25 rem/hr 10m Alberto Fasso et al